Process for treating polyamide materials



A March 12, 1968 J. E. SWALLOW PROCESS FOR TREATING POLYAMIDE MATERIALS 2 Sheets-Sheet 1 Filed May 22, 1963 u 0 2 s A m 0 o o 6% O D 4 m A .0 W 6 T .0 0C 00 00 m 59 0 Q 8 O O O m 5 DAYS IN WATER REATED soc FIG.2

DAYS IN WATER EFFECT OF DISTILLED WATER AT VARIOUS TEMPERATURES ON TENACITY 0F UNDRAWN NYLON.

INVENTOR. JOHN E. SWALLOW March 12, 1968 J. E. SWALLOW PROCESS FOR TREATING POLYAMIDE MATERIALS 2 Sheets-Sheet 2 Filed May 22, 1965 0 O O O O 5 4 3 2 l n Pu 000. X

zOEhEOmmd wmmzm HOURS AT 70C COMPARISON OF RATE OF DETERIORATION OF TREATED 8 UNTREATED 2|N.DIA. ROPES OF UNDRAWN NYLON.

FIG. 3.

INVENTOR.

JOHN E. SWALLOW BY H.777. W, M A. M

United States Patent 3,373,055 PROCESS FOR TREATING POLYAMIDE MATERIALS John Edward Swallow, Farnborough, England, assignor to Minister of Aviation, in Her Majestys Government of the United Kingdom of Great Britain and Northern Ireland, London, England Filed May 22, 1963, Ser. No. 282,427 4 Claims. (Cl. 117--138.5)

This invention relates to the treatment of fibrous forms of the long chain polyamide known as nylon, particularly to what is commonly known as undrawn nylon.

For convenience the term nylon will be used throughout. It is to be understood, however, that although the treatment has been found to be most beneficial to undrawn nylon, the invention is not limited thereto but may be utilized for the treatment of any nylon.

The chemical and physical properties of nylon are liable to deteriorate if it is stored or used in damp or wet conditions or in sunlight. This deterioration causes obvious detrimental changes in the chemical and physical properties and is accelerated by heat, even by gentle warmth.

Various chemical treatments for limiting deterioration have been proposed but no entirely satisfactory process is known.

According to the present invention a process of treating nylon to increase its resistance to deterioration comprises bringing it in contact with S-hydroxyquinoline dissolved in Water and/or one or more organic solvents.

The 8-hydroxyquinoline is commonly known as oxine.

Preferably the oxine is employed in a heated aqueous saturated solution and, in the case of made up fibrous materials such as yarns, cords, ropes and fabrics an impregnation treatment is advantageously used.

An example typical of the manner of performing the process of the invention will now be described.

In this example the specimen was a 3 inch circumference cable laid rope of undrawn nylon.

A saturated aqueous solution of oxine was prepared by adding oxine continuously to water and stirring Whilst heating the bath at 60 C., the addition continuing until excess oxine remain undissolved, about 1 ounce of oxine being required per gallon of water. The rope was immersed in the heated bath and left for 3 days until impregnation was complete and thereafter removed and dried. The treatment coloured the rope yellow-brown.

The simplicity of the process as described in the example illustrates one of its very important advantages.

In performing the process, it is usual first to impregnate test specimens of the nylon to be treated to determine the time of immersion of a given specimen necessary for complete impregnation. Visual evidence of impregnation can be obtained by treating the impregnated material with a 1% solution of ferric chloride which induces an obvious colour change in the impregnated region.

The following Tables 1 and 2 and the accompanying drawings illustrate the properties of undrawn nylon in various forms after treatment according to the process of the invention.

In the tables the column headed environment shows the nature of the treatment and the experimental test environment.

FIGURES 1 and 2 are graphical illustrations of the tenacity retention of undrawn nylon rope yarns in the treated and untreated state when immersed in distiiled water at vairous temperatures. In each figure, the curve relating to the treated yarn is labelled while the remaining curves therein relate to untreated yarns.

FIGURE 3 is a graphical illustration of the rate of de 5 TABLE 1.EFFEOT 0F TEMPERATURE AND CONDITIONS ON THE TENACITY RETENTION OF BOBBIN UND RAWN NYLON YARN Percentage tenacity Temperretention after Environment agige, (days)- Water 6O 0 Saturated oxine 60 100 100 100 Treated with saturated ox transferred to water, 60 100 100 100 100 TABLE 2.TENAOITY RETENTION OF 2 IN. ROPE YARNS AT 60 C. IN VARIOUS ENVIRONMENTS Percentage tenacity retention of 2 in. rope yarns at 60 C. Environment after (days)- Saturated oxine in water 100 100 100 100 100 100 100 Treated with oxine; washed; transferred to water 100 100 100 100 100 Treated with water for 1 day; transterred to saturated oxine 95 95 95 20 Treated with water for 2 days; transferred to saturated cxine 95 95 95 Treated with water for 3 days; transferred to saturated oxine 95 90 70 Treated with water for 4 days;

transferred to oxine 95 95 80 Treated with water for 5 days;

transferred to saturated oxine 65 65 65 Treated with water for 6 days;

transferred to saturated oxine 50 50 50 Treated with oxine in acetone;

transferred to water 100 100 100 100 100 Treated with substituted urine in water; washed; transferred to water containing anatase TiO 100 100 100 100 100 30 Treated with 10 percent H202 at 20 O.ior4days s- 100 100 100 100 100 100 Treated with saturated oxines;

washed; transferred to n/10 formic acid 100 100 100 100 Treated with oxine; oxygen bubbled continuously 100 100 100 100 3,373,055 Patented Mar. 12, 1968 gradation measured as energy absorption of treated and untreated ropes made from undrawn .nylon rope yarns and subjected to heating at 70 C.

Referring to the tables and drawings it will be seen that the resistance of nylon to deterioration is very greatly improved by treatment according to the new process.

It has also been found that nylon generally, particularly undrawn nylon, suffers no marked reduction in its energy absorbing characteristics or unacceptable changes in other physical properties, such as its handling properties, as a result of treatment by the new process.

It is already known that S-hydroxyquinoline is useful as a Water repellent and antiseptic coating for fibrous cellulosic materials, such as paper and wood (see Stone, US. Patent No. 2,021,137), and its copper salt, copper- S-quinolinolate, is used successfully as a fungus-proofing agent for cellulosic (cotton) fabrics and cords (see Benignus, US. Patent No. 2,381,863). However, nylon (unlike cellulosic materials) is inherently fungus-resistant, and it was thus unforeseeable that its storage stability would be benefited by a treatment with S-hydroxyquinoline. Nevertheless, I have found unexpectedly that tenacity loss and other chemical and physical deterioration of nylon during storage which presents a particular pressing problem in the case of undrawn nylon rope (and to a somewhat lesser degree in other nylon products such as textiles), is very considerably reduced, and even eliminated, by treatment with S-hydroxyquinoline.

While the specific examples of the foregoing specification describe certain preferred nylon treatments in accordance with my invention, it will be clear to the expert that the results of my invention may be achieved by suitable changes and modifications within the skill of technologists having ordinary experience. Such changes and modifications are deemed to be encompassed within the scope of my invention, which I now proceed to define by the appended claims.

I claim:

1. A process for treating nylon to increase its resistance to deterioration consisting of the immersion of said nylon in a saturated solution of aqueous 8-hy-droxyquinoline for a time sufiicient to impregnate said nylon, removing said impregnated nylon from said solution and drying the same.

. 2. The process according to claim 1 in which said solution is maintained at a temperature of about 60 C.

3. The process according to claim 1 wherein said nylon is in the form of'undrawn fi bers.

4. The process of stabilizing undrawn nylon rope against tenacity loss consisting of the immersion of said rope in a heated saturated aqueous solution of 8-hydroxyquinoline for a time suflicient to impregnate said rope,

removing said impregnated rope from solution and drying same.

References Cited UNITED STATES PATENTS Kuhn et al 117-138.8 X Roth 117-1388 X Tucker 26045.8 X Benignus 117-138.5 Cox 26045.8 Stamatoflf 260-45.8 Darby et a1 117-138.8 X Benignus 117-138 Miller et a1 117-1388 X FOREIGN PATENTS WILLIAM D. MARTIN, Priamry Examiner.

MURRAY KATZ, Examiner.

20 R. I-IUSACK, Assistant Examiner. 

1. A PROCESS FOR TREATING NYLON TO INCREASE ITS RESISTANCE TO DETERIORATION CONSISTING OF THE IMMERSION OF SAID NYLON IN A SATURATED SOLUTION OF AQUEOUS 8-HYDROXYQUINOLINE FOR A TIME SUFFICIENT TO IMPREGNATE SAID NYLON, REMOVING SAID IMPREGNATED NYLON FROM SAID SOLUTION AND DRYING THE SAME. 